1. Field of the Invention
The present invention relates to a different materials joint structure which is formed by friction stir welding of different materials, an iron member and an aluminum member.
2. Description of the Related Art
For example, International Publication No. WO2013/027474 (Patent Document 1) discloses a friction stir welding tool including a probe and a holder. The friction stir welding method refers to a welding method in which the pin portion at the distal end of the probe is rotated at a high speed, the materials to be joined are allowed to plastically flow due to the frictional heat generated between the pin portion and the materials to be joined, and the materials to be joined are joined integrally.
This friction stir welding requires a tool which includes a probe having a pin portion and a holder holding this probe. In addition, since the replacement frequency for replacing the exhausted probe by a new probe is high, it is preferable to easily perform the operation of replacing the probe from the holder.
In addition to the above, Patent Document 1 discloses a technical idea capable of easily replacing the probe and the holder thanks to the improved structures of the probe and the holder.
However, Patent Document 1 does not disclose or suggest anything concerning, for example, reduction of the frequency of replacing the probe, demand to enhance the strength of the portion of the iron member, and the materials to be joined for improving the friction stir welding property.